A computer responds to an interrupt request signal by pushing onto the stack the contents of PC and the current PSW (program status word). It then reads a new PSW from memory from a location given by an interrupt address symbolized by IAD. The first address of the service program is taken from memory at location IAD + 1. 

a. List the sequence of microoperations for the interrupt cycle.

b. List the sequence of microoperations for the return from interrupt instruction.